Synthesis of single-crystalline sp-carbon-linked covalent organic frameworks through imine-to-olefin transformation.

sp-carbon-linked covalent organic frameworks (spc-COFs) are crystalline porous polymers with repeat organic units linked by sp carbons, and have attracted increasing interest due to their robust skeleton and tunable semiconducting properties. Single-crystalline spc-COFs with well-defined structures can represent an ideal platform for investigating fundamental physics properties and device performance. However, the robust olefin bonds inhibit the reversible-reaction-based crystal self-correction, thus yielding polycrystalline or amorphous polymers.

Hypercrosslinked Metal-Organic Polyhedra Electrolyte with High Transference Number and Fast Conduction of Li Ions.

Solid-state electrolytes (SSEs) with high Li-ion transference numbers and fast ionic conductivity are urgently needed for technological innovations in lithium-metal batteries. To promote the dissociation of ion pairs and overcome the mechanical brittleness and interface defects caused by traditional fillers in polymeric electrolytes, we designed and fabricated a cationic hypercrosslinking metal-organic polyhedra (HCMOPs) polymer as SSE. Benefiting a three-component synergistic effect: cationic MOPs, branched polyethyleneimine macromonomer and polyelectrolyte units, the Li-HCMOP electrolyte possesses a high Li-ion conductivity, a high Li-ion transference number and a low activation energy.

Self-Polycondensation Flux Synthesis of Ultrastable Olefin-Linked Covalent Organic Frameworks for Electrocatalysis.

Creating new functional materials that efficiently support noble metal catalysts is important and in high demand. Herein, we develop a self-polycondensation flux synthesis strategy that can produce olefin-linked covalent organic framework (COF) platforms with high crystallinity and porosity as the supports of Pd nanoparticles for electrocatalytic nitrogen reduction reaction (ENRR). A series of "two in one" monomers integrating aldehyde and methyl reactive groups are rationally designed to afford COFs with square-shaped pores and ultrahigh chemical stability (e.

Bottom-Up Synthesis of Covalent Organic Frameworks with Quasi-Three-Dimensional Integrated Architecture via Interlayer Cross-Linking.

Developing strategies to enhance the structural robustness of covalent organic frameworks (COFs) is of great importance. Here, we rationally design and synthesize a class of cross-linked COFs (COFs), in which the two-dimensional (2D) COF layers are anchored and connected by polyethylene glycol (PEG) or alkyl chains through covalent bonds. The bottom-up fabrication of these COFs is achieved by the condensation of cross-linked aldehyde monomers and tritopic amino monomers.

Solvent-Free Synthesis of C=N Linked Two-Dimensional Covalent Organic Frameworks.

Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with well-defined structures and tunable functionalities, which have fascinating applications in a wide range of fields. However, the synthetic procedures of COFs are mainly confined to the solvothermal synthesis method which usually requires harsh experimental conditions. In this work, an effective solvent-free synthesis method to construct a series of two-dimensional (2D) COFs including imine-linked, azine-linked, β-ketoenamine-linked, which avoids the complicated solvent screening process and most of the disadvantages of solvothermal methods is developed.

Bottom-Up Synthesis of 8-Connected Three-Dimensional Covalent Organic Frameworks for Highly Efficient Ethylene/Ethane Separation.

Developing cost-/energy-efficient separation techniques for purifying ethylene from an ethylene/ethane mixture is highly important but very challenging in the industrial process. Herein, using a bottom-up [8 + 2] construction approach, we rationally designed and synthesized three three-dimensional covalent organic frameworks (COFs) with 8-connected networks, which can selectively remove ethane from an ethylene/ethane mixture with high efficiency. These COF materials, which are fabricated by the condensation reaction of a customer-designed octatopic aldehyde monomer with linear diamino linkers, possess high crystallinity, good structural robustness, and high porosity.

Construction of Covalent Organic Frameworks via Three-Component One-Pot Strecker and Povarov Reactions.

Postsynthetic modification (PSM) has been demonstrated to be a powerful method for achieving new covalent organic frameworks (COFs) via single-step or multistep organic functional group transformations on established COF frameworks. PSM, however, might sometimes lead to collapse of the COF framework, decreases in crystallinity, or low postsynthetic yield due to the inherent limit of solid-state synthesis. Herein we report, for the first time, a new synthetic strategy that can generate new COFs via multicomponent one-pot reactions.

Cu-catalyzed C-H amination/Ullmann N-arylation domino reaction: a straightforward synthesis of 9,14-diaryl-9,14-dihydrodibenzo[a,c]phenazine.

A Cu-catalyzed C-H amination/Ullmann N-arylation domino reaction of phenanthrene-9,10-diamines with aryl iodides has been developed, which provides a straightforward and facile access to 9,14-diaryl-9,14-dihydrodibenzo[a,c]phenazine. This reaction features readily available starting materials and simple experimental operation.